Britain narrowly avoided going the same way as New Zealand, who were victims of arguably the greatest shock in sevens history when Japan beat them 14-12, while they also lost World Cup winner Sonny Bill Williams to an Olympics-ending injury.

The Japanese, emulating the spirit of their 15-a-side team when they unforgettably beat South Africa at last autumn’s World Cup in Brighton, were a conversion away from drawing with Britain, but the last-gasp kick was missed and GB held out for a 21-19 victory.

Two James Rodwell tries put Britain in the driving seat, but Japan had no intention of rolling over, and they fought back to level the contest through converted scores from Lomano Lemeki and Katsuyuki Sakai.

Marcus Watson, brother of England star Anthony Watson, then touched down to put the Pool C leaders back in front, only for Lemeki’s second try to set up a nerve-shredding climax that narrowly saw Britain move towards the quarter-finals ahead of tackling New Zealand on Wednesday.